Scraped-surface heat exchangers are commonly utilized in aseptic processing of foodstuffs. These heat exchangers are preferred because of their capability to process heat-sensitive, viscous products, and minimize the extent of burn-on, or fouling on the heat transfer surface. Such heat exchangers are commonly marketed under the trade names, for example, Votator®, Thermutator®, Contherm®, and Terlotherm®. Waukesha Cherry-Burrell, Delavan, Wis., for example, manufactures such heat exchangers.
Scraped surface heat exchangers are particularly suitable for use in the foodstuff industry where they are used for refrigerating or heating of fatty products, bakery products, and dairy products such as margarine emulsion and ice cream. A heat exchanger of this type may include a cylindrical treatment chamber or product tube, a rotor such as a mutator shaft, arranged in the chamber and a number of blade rows including a number of successively arranged blade scrapers mounted on the rotor so as to make the blades scrape the inner surface of the chamber during operation. A refrigerant or a heating medium, e.g., ammonia, freon, glycol, hot water or steam, may be generally circulated on the outside of the treatment chamber and may further provide heat exchange by a conventional heat exchange process. A cylindrical treatment chamber or product tube is typically heated or cooled so that a treated product will undergo a change of temperature as it passes through the scraped surface heat exchanger. The treated product is generally introduced, in some embodiments, under pressure at one end of the heat exchanger and is generally designed to leave the heat exchanger at its opposite end. The scraping of the product off the inner surface of the chamber during its passage through the heat exchanger thereby provides a considerably improved heat transmission.
In a scraped surface heat exchanger, the inside of a product tube is scraped with blades mounted on the rotor or mutator shaft which rotates within the product tube. The product tubes, along with the mutator shafts, may be manufactured with different lengths to provide various heat exchanger areas. These units can be installed in either a horizontal or vertical position. At various times, it may be necessary to service the scraped surface heat exchanger, for instance, to replace mechanical seals, replace/inspect worn blades, or to clean the product tube area. To service the unit, access space must be provided to remove the mutator shaft from the product tube.
Typical product tube lengths may vary, for instance, from one to two feet or traverse greater lengths such as seven to nine feet. For longer length configurations, product tubes mounted in a vertical configuration require access space generally equal to the length of the product tube underneath the vertical unit of the scraped surface heat exchanger. In a horizontal configuration, access space, generally equal to the length of the product tube, is typically provided in front of a horizontal unit of the scraped surface heat exchanger. Thus, considerable space requirements can be necessary in either vertical or horizontal configurations requiring, for example, excessive ceiling heights or broad servicing lengths in order to allow shaft insertion/removal during scraped surface heat exchanger assembly/disassembly. This may provide difficulties for service technicians servicing such scraped surface heat exchangers.
Accordingly, it is desirable to provide a method and apparatus that can facilitate lower vertical and horizontal space requirements when servicing scraped surface heat exchangers.